Such a device is known from DE 44 31 761 C2 (U.S. Pat. No. 5,528,895) and is shown in FIGS. 1 and 1a. In this, fibres are guided through a fibre bundle passage 13 on a twisted fibre guidance surface, which exhibits a “rear” edge 4b about a “front” edge 4c. The fibres are then guided around what is referred to as a needle 5 into a yarn passage 7 of what is referred to as a spindle 6, whereby the rear part of the fibres are rotated by means of an eddy current generated by nozzles 3 about the front part of the fibres, already located in the yarn passage, with a yarn being formed as a result. Once this has been done, spinning takes place, as is described later in connection with the invention.
The element referred to as the needle, and its tip about which the fibres are guided, is located close to or in the inlet aperture mouth 6c of the yarn passage 7 and serves as what is referred to as a false yarn core, in order as far as possible to prevent or to reduce the possibility that, due to the fibres in the fibre bundle passage, an impermissibly high false twist of the intertwined fibres occurs, which would at least interfere with the formation of the yarn if not even preventing it altogether.
FIG. 1b shows this aforementioned prior art encumbered with disadvantages (DE 41 31 059 C2, U.S. Pat. No. 5,211,001), in that, as is known from DE 44 31 761, FIG. 5, the fibres are not guided consistently about the needle as shown in FIG. 1a, but are guided on both sides of this needle against the inlet aperture mouth of the yarn passage, which apparently interferes with the binding of the fibres and apparently can lead to a reduction of the strength of the spun yarn.
FIG. 1c shows a further development of FIG. 1, or 1a respectively, in that the fibre guidance surface 4b, as can be seen, is designed in a helical shape, and the fibres are accordingly likewise guided in helical form in their course from the clamping gap X as far as the end e5 of the helical surface, and are then wound, still in helical form, about a fibre guidance pin, similar to the fibre guidance pin 5 of FIG. 1, before the fibres are acquired by the rotating air flow and twisted to form a yarn Y. In this situation, it can be seen that the rear ends of the fibres f″ are bent about the mouth part of the spindle 6, and in this context are taken up by the rotating air flow and wound around the front ends, which are already located in the center of the fibre run, in order to form the yarn as a result.
FIG. 1c corresponds to FIG. 6 from DE 19603291 A 1 (U.S. Pat. No. 5,647,197), whereby the identification references of the spindle 6, the yarn passage 7, and the venting cavity 8 have been adopted from FIG. 1, while the element e2, which has a similar function to the needle 5 of FIGS. 1 to 1b has been left as it was. It can likewise be seen from this FIG. 1c that the fibres are transferred from a helical formation to the inlet of this spindle.
A further prior art from the same Applicants is specified in JP 3-10 64 68 (2) and seen in FIGS. 1d and 1e, which, by contrast with FIG. 1, does not exhibit a needle, but rather a truncated cone 5a with a flat fibre guidance surface, which is a part of the fibre guidance channel 13, and the tip of which is arranged essentially concentric to the fibre guidance run 7. The purpose of this cone is the same as that of the tip 5, namely of producing what is referred to as a false yarn core in order to prevent the fibres from being incorrectly twisted; in other words, that a false twist occurs from the tip backwards against the clamping gap of the output rollers, which would at least in part prevent a true twist of the fibres such as to form the yarn.